Mouse event wait freezes when called from button

Question

I have a method which brings up a transparent window overlay so I can indicate corner points of a rectangular onscreen area via clicks.

public Point getClickPoint(){ JFrame frame = new JFrame(""); MyMouseListener mouseL = new MyMouseListener(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setUndecorated(true); makeTranslucent(frame, Float.valueOf(0.40f)); frame.setSize(toolkit.getScreenSize()); frame.setVisible(true); frame.addMouseListener(mouseL); while(!mouseL.done){ try { Thread.sleep(4); } catch (InterruptedException e) { e.printStackTrace(); } } }

When I call this in a normal way it works fine, but if I call it by a button press, then it hangs, doesn't register clicks and eventually freezes.

 Button.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent actionEvent) { getClickPoint(); } }

Is this something to do with the fact this is called originally by an action listener?

Jeffrey · Accepted Answer · 2012-05-26 14:05:28Z

3

You are blocking the Event Dispatch Thread. Since the actionPerformed method will be called on the EDT, your while loop in getClickPoint will prevent the EDT from processing any events (including the mouse events you are waiting for), causing your program to become unresponsive.

If you need to perform time expensive tasks (such as blocking), take a look at SwingWorker.

answered May 26, 2012 at 14:05

Jeffrey

44.9k8 gold badges93 silver badges143 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

mKorbel Over a year ago

this is job for Swing Timer, exclusivelly

skelly Over a year ago

So I made a class called GetPointWorker which extends SwingWorker, whose doInBackground() task is as above. My method now instantiates a new GetPointWorker and calls doInBackground(), but it still freezes. Am I structuring this terribly wrongly?

Jeffrey Over a year ago

@skelly You don't call doInBackground directly. You call execute, and doInBackground will eventually be called on a separate Thread.

Collectives™ on Stack Overflow

Mouse event wait freezes when called from button

1 Answer 1

3 Comments

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Related